A Matter of Balance: An Overview of Pleistocene Occupation History and the Impact of the Last Glacial Phase in East Timor and the Aru Islands, Eastern Indonesia

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This paper explores the subsistence records from cave sites with Pleistocene-aged deposits in East Timor and the Aru Islands during the Last Glacial Maximum (LGM), and discusses these records within the context of the limited archaeological evidence for LGM occupation from elsewhere in the Indonesian Archipelago. Although Timor and the Aru Islands are at similar latitudes, the onset of aridity had markedly different impacts on the settlement and subsistence choices available to hunter-gatherers in these two regions. We suggest that the different occupation trajectories seen in Timor and Aru during the LGM are related, at least in part, to biogeographic contrasts across the Indonesian Archipelago.

Keywords: Last Glacial Maximum (LGM), East Timor, Aru Islands, eastern Indonesia, Pleistocene fauna.



Recent research in East Timor and the Aru Islands in eastern Indonesia (Figure 1) has brought to light some significant differences in the occupation record of these islands, with the most pronounced contrast relating to the Last Glacial Maximum (LGM). Several sites with long sequences beginning between ca. 28,000 calBP and 42,000 calBP have now been excavated and analysed from East Timor and Aru. Although at roughly similar latitudes the onset of aridity appears to have had very different impacts on hunter-gatherers in these two regions. These different histories during the LGM are probably related at least in part to biogeographic differences across the Indonesian Archipelago. Unlike the continental faunas of Sundaland and Sahuland, the oceanic faunas of Wallacea (Sulawesi, the Moluccas and Lesser Sunda Islands, including Timor) are 'unbalanced' (sensu van den Bergh et al. 2001), reflecting their isolation from mainland source areas and their relatively small landmass areas. In contrast, the contemporary fauna of Aru is more diverse and 'balanced', reflecting a closer connection with Sahul until the terminal Pleistocene, and the late Pleistocene fauna was richer again (Aplin and Pasveer 2005). This paper explores the evidence of Pleistocene colonisation and subsistence behaviour for East Timor and the Aru Islands, and compares these records with the more limited archaeological evidence for LGM occupation from elsewhere in the Indonesian Archipelago.

LGM Palaeoecology and Palaeoclimate

Around 30,000 yrs ago global climates and environments experienced a dramatic shift, marked most conspicuously by a rapid buildup of glacial ice in the northern hemisphere and by an associated, sharp fall in global sea level (Lambeck and Chappell 2001:680). This paper is primarily concerned with the effects of decreased sea levels and climate change on human settlement patterns and subsistence in the Indonesian Archipelago during the LGM buildup from 30,000 yrs ago to 25,000 yrs ago and the peak LGM from approximately 25,000 yrs ago until about 15,000 yrs ago. LGM conditions, which correspond approximately with OIS2 in the deep sea core records, persisted with little respite for around 15,000 years. In most areas of the globe it had a dramatic impact on plants and animals and human populations dependent on them for survival. The northern hemisphere story is well known, where advancing ice sheets led to profound changes in vegetation and faunal distributions and rendered many areas unsuitable for human habitation (Gamble et al. 2004). In parts of the southern hemisphere environmental transformations were just as dramatic, with large areas of inland and southern Australia covered with mobile sand desert and cold, dry steppe (Hiscock and Wallis 2005; Hope et al. 2004). High altitude parts of the southern Alps and Tasmania were also ice covered during the height of this phase, which peaked approximately 18,000 yrs BP (or 21,000 calBP; Hope et al. 2004).

Much less is known however about the impact of last glacial phase climates on the tropical equatorial realms. …